The paper looked at nearly 50 years of data testing whether posing facial expressions can lead people to feel the emotions related to those expressions.

“These findings address a critical question about the links between our internal experience and our bodies—whether changing our facial expression can alter the emotions we feel and our emotional response to the world,” says coauthor Heather Lench, an associate professor and head of the psychological and brain sciences department at Texas A&M University.

“…psychologists have actually disagreed about this idea for over 100 years.”

“Conventional wisdom tells us that we can feel a little happier if we simply smile. Or that we can get ourselves in a more serious mood if we scowl. But psychologists have actually disagreed about this idea for over 100 years” says lead author Nicholas Coles, a researcher from the University of Tennessee.

These disagreements became more pronounced in 2016 when 17 teams of researchers failed to replicate a well-known experiment demonstrating that the physical act of smiling can make people feel happier.

Using a statistical technique called meta-analysis, the team combined data from 138 studies testing over 11,000 participants from all around the world. According to the meta-analysis, posing facial expressions has a small impact on our feelings. For example, smiling makes people feel happier, scowling makes them feel angrier, and frowning makes them feel more sad.

“We don’t think that people can ‘smile their way to happiness’. But these findings are exciting because they provide a clue about how the mind and the body interact to shape our conscious experience of emotion” says Coles.

“We still have a lot to learn about these facial feedback effects, but this meta-analysis put us a little closer to understanding how emotions work.”